1. Field of the Invention
The present invention relates generally to an electrical equipment. More particularly, the invention relates to a method for connecting wiring, such as power source lines, signal lines and so forth of a plurality of printed circuit boards with each other and a printed circuit board unit with a plurality of printed circuit boards established connection.
2. Description of the Related Art
In the conventionally realized printed circuit board unit, a main board 51 and a subsidiary board 52 are connected through a connector 53 and a connector 54, and the main board 51 and the subsidiary board 52 are secured by a screw 55 so as to prevent disengagement of the connectors 53 and 54 as shown in terms of an example of personal computer in FIGS. 6A and 6B. In the shown personal computer, a power source current 56 flowing out from a power source IC 60 of the subsidiary board 52 flows into a load circuit A61 on the subsidiary board 52 through a power source pattern 57 and to a pin 59 of the connector 53, as shown in FIGS. 7A and 7B. The current flowing into the pin 59 is supplied into a load circuit B62 and a load circuit C63 by a power source pattern 58 of the main board 51 through the connector 53 and the connector 54. In these figures, only connection of the power source lines is illustrated. However, the signal lines are connected through the connectors in similar manner as the power source lines.
In the conventional printed circuit board unit set forth above, the power source lines and the signal lines used in common in the subsidiary board and the main board are connected only by the connectors. Number of pins in the connector becomes larger to require greater space.
The present invention has been worked out in view of the problem set forth above. Therefore, it is an object of the present invention to provide a printed circuit board unit which has smaller number of pins in connectors for connection of wiring (signal lines and power source lines) between a plurality of printed circuit boards for increasing mounting space of the board and interconnection method of wiring between printed circuit boards.
According to one aspect of the present invention, an interconnection method of wiring of printed circuit boards for interconnecting wiring of a plurality of printed circuit boards of electrical equipment, comprises:
step of electrically connecting a part of wiring of the printed circuit boards with each other by connectors; and
step of electrically connecting remaining portion of wiring of the printed circuit boards with each other by a screw formed of an electrically conductive body in conjunction with fixing the printed circuit boards by the screw.
According to another aspect of the present invention, a printed circuit board unit comprises:
a plurality of printed circuit boards having wiring formed thereon;
a part of the wiring on the printed circuit boards electrically connected through connectors;
a screw formed of electrically conductive body and fixing the plurality of printed circuit boards with preventing the connectors from disengaging from each other; and
remaining part of the wiring on the printed circuit boards electrically connected through the screw.
In practice, power source lines and/or signal lines of the printed circuit boards are electrically connected with each other by the screw.
With the present invention, the screw for fixing a plurality of printed circuit boards is used as a part of wiring to reduce number of pins of the connectors to increase mounting space on the printed circuit board.